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WASHINGTON UNIVERSITY. . 

Theses for the Degree of Doctor of Philosophy. 



Xo. C. 



A DISEyVSE OF TAXODIUM KNOWN AS PECKINE8S, 

ALSO A SIMILAR DISEASE OF LIBOCEDRUS 

DECURRENS. 



HERMANN VON SCHRENK, 

i'-. ■^^ ii . 

fj B. S., Cornell University* 'fl3; A. M., Harvard University, '94; 



I 



Camlidate for tlic Dcirrcc ,it' Doctor of Pliilo^ophy in Botany 



Printed bi advance from the 
Klevmth Annual Report of the ^^ssovn' Botanical Garden. 



St. Louis, Mo., Jiiiif h Ism. 






^to 



SCIENTIFIC PAPERS. 



A DISEASE OF TAXODIUM DISTICHUM KNOWN AS PECKI- 
NESS, ALSO A SIMILAR DISEASE OF LIBOCEDRUS DECUR- 
RENS KNOWN AS PIN-ROT.* 



BY HERMANN VON SCHRENK. 



INTRODUCTION. 



The diseases of forest trees had attracted attention for 
many years before any attempt was made to arrive at an 
understanding of their true nature. With the investigations 
of Th. IIartig,t Schacht,! and WiUkomm,§ a beginning was 
made, but not until the epoch-making researches of R. 
Hartig,|| were some of the complex relations between 
diseased trees and the exciting causes made clear. In 
England, Marshall- Ward has paid some attention to the 
diseases of trees, but in this country few have given this 
subject much study. 

A tree may be diseased because of the natural decadence 
of its vital forces incident to old age, it may be influenced 
by abnormal physiological conditions, or its functions may 
be impaired by the activities of a disturbing organism. 



* A thesis presented to the Faculty of Washington University for the 
degree of Ph. D., April, 1899. 

t Hartig, Th. Abhandlung iiber die Verwandlung der polycotyle- 
donischen Pflanzenzelle in Pilz u. Schwammgebilde, u. die daraus 
hevorgehende Faulniss des Holzes. 1833. 

X Schacht, Hermann. Der Baum, Studien iiber Bau u. Leben der 
hoheren Gewiichse. Berlin. 1860. 

§ Willkomm, M. Die mikroscopischen Feinde des Waldes. Dresden. 
1866. 

II Hartig, R. Wichtige Krankheiten der Waldbaume. Berlin. 1874.— 
Die Zersetzungserscheinungen des Holzes, etc. Berlin. 1878. 

Separates issued June 3, IS99. ^ 



MISSOURI BOTANICAL GARDEN. 

Examples of the first class of disease need not be given ; 
the root rot of pines * is an example of the second class, 
and the numerous fungi (and insects) attacking di:fferent 
parts of a tree come under the third class. It is particu- 
larly the latter class which Hartig has studied and with 
some of which the present paper is to deal. 

The fungi attacking trees may be divided for convenience 
into such as are strictly parasitic, like the Peridermiums, 
Exoasci, Gymnosporaugiums, etc., and such as are not. 
Among the latter class one finds various grades, going from 
the strictly parasitic to the strictly saprophytic forms, 
including the facultative saprophytes (of De Bary) or 
hemiparasites, the true saprophytes, and the facultative 
parasites (De Bary), or hemisaprophytes. Of the fungi 
which attack the trunks of trees, i. e., the wood already 
formed, few are strictly parasitic or hemiparasitic ; the 
majority are hemisaprophytes, for although normally 
growing on dead matter they may occasionally become 
truly parasitic. Tubeuf f mentions a number of such fungi, 
among them several common in this country, such as 
Trametes Pini, Polyporus fomentarius ^ Polyporus sul- 
phureus^ and others. Trametes Pini may serve as a good 
example. When growing on species of pine, such as Pinus 
palustris^ Pinus Strobus, Pinus echinata, it flourishes in 
the heartwood of these trees as a strict saprophyte, i. e., 
on the dead wood. The resinous contents of the living: 
wood prevent its becoming parasitic. On the other hand, 
when growing on Abies balsamea or Picea nigra it becomes 
a parasite, growing likewise in the living wood and ulti- 
mately killing the tree. The diseases to be discussed in 
the following are due to hemisaprophytes, as they affect the 
heartwood of the trees and never enter the living parts of 
the trunks. 



♦ Hartig, R. Zersetzungserscheinungen, etc. 75. 
t Tubeuf, C. Freiherr von. Diseases of plants 5. (English edit, by 
W. G. Smith. 1897.) 
2 



DISEASES OF TAXODIUM .AND LIBOCEDRUS. 

Some years ago, while collecting in the cypress swamps 
of Arkansas, a peculiar defect of the bald cypress, Taxodium 
distichum^ was noticed, popularly known as " pecky " or 
" peggy " cypress. Further investigation showed that the 
defect was prevalent wherever the cypress grew in abun- 
dance, and that fungus threads were constantly associated 
with the pecky wood. This led to the investigations here 
recorded. 

In pursuing these investigations little could have been 
done without the generous assistance of numerous lumber 
companies. Among those to whom thanks are due are the 
Lutcher & Moore Cypress Lumber Co. of Lutcher, La. ; 
Mr. M. E. Leming of Cape Girardeau, Mo. ; Towle Bros, of 
Towle, Placer Co., Cal. ; the Stimson Mill Co. of Ballard, 
Wash.; Mr. A. J. Johnson of Astoria, Oregon, and Birce 
& Smart of Emigrant Gap, Cal. 

To Dr. W. G. Farlow and Dr. H. W. Harkness I am 
indebted for many suggestions; to Dr. J. J. Friih of 
Ziirich, for his courtesy in answering some questions ; to 
Maj. B. M. Harrod of New Orleans for assistance in 
obtaining buried cypress logs, and to Prof. C. R. Sanger 
and Dr. G. Alleman for suggestions on chemical questions. 
I also take pleasure in expressing thanks to Dr. Wm. 
Trelease for much encouragement and generous assistance. 

THE DISEASE OF TAXODIUM KNOWN AS " PECKY " CYPRESS. 

Historical. 

The first mention of the disease of cypress known as 
«< pecky," or "peggy" cypress, is made by Dickeson & 
Brown.* They say of it : " That species of decay to which 
it [the cypress] is most Uable, shows itself in partial or de- 
tached spots at greater or less distance, but often in very 
close proximity to each other. It is a decomposition of the 



* Dickeson, Montroville W., & And. Brown. On the cypress timber of 
Mississippi and Louisiana. (Am. Journ. of Science, ii. 5 : 15. 1848.) 

3 



MISSOURI BOTANICAL GARDEN. 

wood fiber to which the tops and central parts are the most 
exposed, and which, when affected, appear as if operated 
upon by worms. . . . Timber affected in this way is 
denominated by raftsmen, '' peckij.'' " 

Sargent* says of the cypress: "It is often injured, 
especially west of the Mississippi river, by a species of 
Daedalea not yet determined, rendering it unfit for lumber." 
FarloWjt writing in Sargent's Silva, notes that " a species 
of dry rot in living timber often diminishes its value, and 
in Louisiana and Mississippi is said to affect at least one- 
third of all the trees." Eather recently Koth J mentions 
its occurrence in the South, and briefly describes its appear- 
ance. Beyond these few notes, nothing appears to have 
been said of the disease. 

Occurrence. 

Taxodium distichum is now found from South Carolina 
to Florida ( some trees occur as far north as New Jersey § ) 
thence to Louisiana and northward as far as southern Indiana \ 
and southeast Missouri. Wherever the cypress grows to 
any size, it shows the " pecky " disease, the prevalence of 
which appears to be very variable. The exact percentage is 
difficult to ascertain as it varies materially with the locality. 
Roth (1. c.) says that 30% of the entire cypress supply is 
damaged by this disease. As a rule one may say that 
wherever the cypress grows, one will find it ♦' pecky," and 
that there are no regions where all trees are sound. As 
for particular localities, Eoth mentions a tract of land in 
Florida, which had to be abandoned entirely on account of 
" pegginess." In the Mississippi Valley by actual count it 

♦ Sargent, C. S. Forest trees of North America. 10th Census 
9:184:. 1883. 

t Sargent, C. S. Silva of North America 10 : 160. 1896. 

X Roth, Filibert. Progress in timber physics — ''Bald cypress." 
(U. S. Dept. of Agr., Div. of Forestry, Circular No. 19: 3. 1898.; 

§ Hollick, A. (Cypress in N. J., read before Bot. Soc. Am. 1898.) 

1 Wright, John S. — Notes on cypress swamps in Knox Co., Indiana. 
(Proc. Ind. Acad. Sci. 1897 : 172). 
4 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

has beenfound that the trees near their northern limit are less 
frequently diseased than the more southern ones. As it is al- 
most impossible to tell whether a tree be pecky or not before 
it is cut down, all actual counts had to be made where lumber 
mills were cutting the trees, and as they usually cut all 
trees, even those liable to be diseased, a fair estimate for that 
particular locaUty could be made. In St. James Parish, 
Louisiana, 397 trees out of 400 were found diseased to a 
greater or less extent. From circulars sent to various lum- 
ber concerns the following estimates are made, which may 
be considered as much under- rather than overdrawn. 
Apalachicola, Fla., 10-15%. New Orleans Cypress Lum- 
berCo.,99%. Ramos, La., 15%. Georgetown, S.C., " con- 
siderable. ' ' These figures refer to ' ' peckiness ' ' in logs used 
for lumber, and do not have any reference to the tops of 
trees, which are the first parts to be " pecky." The char- 
acter of the ground seems to have little if any effect on the 
prevalence or extent of the disease. The cypress trees 
normally grow with their root system in water for at least a 
part of each year, and in many places, particularly along the 
coast, during the entire year. This rather unusual habit of 
growth together with the appearance of the puzzhng form- 
ation of knees has led many to connect the facts of growing 
in water, development of knees, and " peckiness." So far 
no evidence is forthcoming to show any connection between 
these factors. 

Name. 

When a diseased cypress tree is cut down, the heart wood 
appears as if a large number of holes had been bored with 
a ^ inch bit which had been withdrawn, leaving the shav- 
ings, finely divided, within the hole. It is this pecuhar ap- 
pearance which has given rise to the different popular terms 
applied to the disease. Dickeson & Brown (1. c.) refer to 
it as <' pecky." In the Mississippi VaUey and throughout 
Louisiana I have found the diseased wood called " pecky " 

5 



MISSOURI BOTANICAL GARDEN. 

cypress, and the disease itself called the ' ' peck. ' ' In North 
Carolina the term '* botty " (see Eoth 1. c.) is more or less 
common because of the supposed action of a larva, the 
" bot." "Peggy " is frequently used in Georgia and Flor- 
ida, where correspondents also give the term ' ' puck. ' ' Near 
pinelands " punk " is used by pine lumbermen, accustomed 
to the decay caused by Trametes Pini. It is almost useless to 
speculate as to the origin of the various terms, and a choice 
between them is difficult. Having found the term ' ' pecky ' ' 
most widely known as well as the one which was first used, 
I shall call the disease by that name throughout this paper. 

Appearance of Wood. 

The diseased wood appears full of holes (PI. 1, fig. 2), 
varying in width from ^-| inches. These holes are found 
in the heartwood only, and in trees after they have reached 
the age of 125 years or thereabouts. Young trees of 
Taxodium are comparatively rare, but such as were noted, 
varying in age from 50 to 125 years, were always free from 
any defect. The holes in the wood extend longitudinally 
up and down in the trunk, parallel to the wood fibers. The 
holes never extend transversely. They are separated from 
one another by layers of wood apparently perfectly sound. 
They vary in length from \ inch to 6 inches, or longer 
in some cases; most frequently they are 4-5 inches 
long. They end bluntly at both ends, and as a rule do not 
communicate. Frequently trees are found in which some 
holes do open into one another, but these are rather 
exceptional. The holes are filled with a yellow brown 
powder which readily crumbles into the finest dust between 
the fingers. The powdery mass does not completely fiU 
the space, showing that much material has been destroyed. 
Occasionally the mass is not entirely composed of the 
powdery substance; stringy fibers, composed of wood cells 
not yet disintegrated, fill the ca\aty, together with much 
finely divided matter. This indicates that the disintegrat- 
6 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

ing factor has not acted uniformly but has caused certain 
parts to decay, while others are spared. A fluffy white 
fungus mycelium, covered with drops of liquid as with 
dew, is oftentimes present, but more often none is to be 
seen amid the dry contents of the holes. Several trees 




Appearance of Wood. 



were found near Mobile, Ala., in which the holes were 
partially filled with a peculiar reddish-brown, soft sub- 
stance having a bright shining fracture. This substance 
adhered firmly to the walls, as if forming a part of the 
wood fibers. It will be described more in detail. Asso- 
ciated with this substance peculiar white needle-shaped 

7 



MISSOURI BOTANICAL GARDEN. 

crystals were found whose identity has not yet been deter- 
mined, as the amount found was too small to admit of 
analysis. This substance had the following properties: 
very light, like fine cotton wool, or cocoon silk, apparently 
very pure; volatilizes at once on platinum (heated) with- 
out burning; insoluble in water, soluble in hot alcohol, 
from which it crystallizes in shapes looking like sea moss ; 
very soluble in petroleum ether, and extremely so in chlo- 
roform; residue colloid, resinous ; melting point 174° C, 
pretty sharp without decomposition; chloroform solution 
does not absorb bromine; subhmes very readily, forming 
beautiful hairlike crystals. 

A number of trees were found in which the holes, instead 
of being filled as stated above, were nearly empty. They had 
a shining white lining ( PI. 4, fig. 3) from which isolated 
white fibers projected into the cavity. The white fibers were 
found to be pure cellulose. 

When the brown contents are brushed out of the holes a 
perfectly even and smooth surface is left on all sides, indi- 
cating a very sharp dividing line between the decayed ele- 
ments and those apparently sound. A board from which 
the powder has been taken looks as if a number of grooves 
had been cut with a gouge chisel (PI. 6). 

In a tree the peckiness starts in the upper part, i. e., the 
majority of the trees are perfectly sound at the base, and 
very much diseased in the upper portion of the trunk and 
the larger branches. The decay may extend but a few 
inches up and down, or for several feet, or through the 
entire length of the tree. The youngest branches in which 
any peckiness was found were 60 years old. Eadially it 
may appear over the entire cross-section or on but one side. 
It is by no means the rule that the innermost rings 
are the first ones to decay (PI. 1) as might be supposed 
from analogy with other timber diseases. A large tree at 
Arbor, Mo., approximately 300 years old, was pecky to 
within 25 ft. of the base, another to within 35 ft. The 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

peckiness in the latter extended upward into two main 
branches for 20 ft. At the points where all recognizable 
traces of the disease ceased, the branches had about 150 
annual rings. A third tree was sound for 60 ft. from the 
base, then became very pecky, the peckiness passing up 
into two or three main branches, and still another was pecky 
3 ft. from the base and upward. The extent of peckiness 
varies, i. e., in one trunk the holes may be several inches 
apart, or scattered all over the cross-section, in another they 
may be confined to the first 150 rings. Nowhere was a 
single tree seen hollow, at least none which was hoUow be- 
cause of an advanced stage of peckiness. In this respect 
this disease aif ects the cypress just as Trametes Pini does 
the pines. One never finds a pine hollow because of 
disintegration caused by Trametes Pini. This is especially 
to be noted, as it will be referred to again. It is a notice- 
able fact that in traveling through cypress forests one 
rarely sees many fallen trees, and where violent wind- 
storms have overthrown any number of trees, these are just 
as often trees sound at the base as those which are diseased. 
In the fall the whole tree falls, i. e., the trunk does not 
break, as do many pines and deciduous trees, in which the 
entire heartwood may have been destroyed, by such a para- 
site as Pohjpoynis sulphureus. The oldest trees e. g., in 
which about 1800 rings were counted (southern Louisiana), 
have the same appearance as those but 200-300 years in age. 

Structure of Diseased Wood. 

The wood of Taxodium is composed of tracheids with 
one or two rows of pits. The growth rings are rather broad, 
the summer wood about one-third the width of the spring 
wood. Eesin passages are wholly wanting, and in their 
stead there are numerous resin cells either scattering or in 
tangential bands.* The amount of resin in the wood is 



* Penhallow, D. p. The generic characters of the N. A. Taxaceae and 
Coniferae. (^Trans. Roy. Soc. Canada ii. 2 : 51. 1896.) 

9 



MISSOURI BOTANICAL GARDEN. 

comparatively small. The diseased wood is darker in color 
than the normal wood, has no tenacity, and when crushed, 
turns into fine powder. These properties lead one to sus- 
pect profound morphological as well as chemical changes. 
A radial section through a rotted hole and the adjacent 
sound wood is represented on PI. 5, fig. 10. The normal 
wood cells (a) show the constituent lamellae of the 
cell-wall plainly. The first noticeable change is in the bor- 
dered pits, which look as if they were corroded, like starch- 
grains in process of solution. This appearance is due to 
drops of resinous oil, which arrange themselves in this 
pecuUar manner (PI. 5, fig. 3) on the walls and within 
the cavity of the pit. When treated with turpentine the 
resin is dissolved and the pits then look smooth. The walls 
at the same time are perforated in many places by colorless 
hyphae; no preference is shown for the pits. As one pro- 
ceeds toward the decayed spot the pits look fragmented ; fin- 
ally peculiar spiral breaks appear extending from the pits and 
passing upward from left to right. The breaks of two adja- 
cent walls cross one another at the pits (e), the lower one 
apparently extending from right to left. The whole cell- 
wall becomes striated, the striae all extending in a spiral line 
from left to right around the wall. Before long the circu- 
lar disc of the pit drops out, leaving a hole with jagged 
outline, which gradually increases in size. The number of 
breaks in the walls has increased, and finally the whole wall 
breaks up into innumerable pieces. The wood, when once 
the disintegration sets in, becomes so very brittle that it is 
very difficult to get good sections. Imbedding the same in 
soft paraffine was found very useful. The longitudinal 
walls grow thinner because of the shrinkage of the middle 
lamella. This gradually disappears, and gives rise to the 
breaks in the wall already spoken of. The shrinkage and 
solution finally has gone so far that only the primary 
lamella is left, which breaks into many pieces. The drop- 
ping out of the more resistant walls lining the pits is char- 
10 



DISEASES OF TAXQDIUM AND LIBQCEDRUS. 

acteristic, and in preparations of much-deca3'^ed wood large 
numbers of the circular discs can be seen floating about. 

The micro-chemical reactions are marked. Any investi- 
gation into the chemical nature of wood substance is apt to 
be rather unsatisfactory. It is possible to record certain 
well-marked reactions, but often their true significance will 
not be apparent, because our knowledge of the complex 
constituents of wood, and particularly of its decomposition 
products, is still so very meager. 

The most characteristic reaction is the one with phloro- 
glucin and HCl. If a section, preferably a transection 
of wood cut so as to include the outer portion of the 
decayed area, and some of the surrounding wood, be treated 
with this reagent, an appearance such as is represented on 
PI. 3, fig. 1, is obtained. The cells of the sound wood 
i. e., wood in which no recognizable morphological 
change has taken place, stain dark red purple. The pri- 
mary lamella stains much deeper (p). Passing to cells 
further inward (towards the diseased spot) the tertiary 
lamellae of some cells no longer stain red purple but yellow 
(d). This yellow coloration increases as one passes on, the 
red decreasing correspondingly, until at a certain stage 
only the primary lameUa is stained red. The pits are the 
first areas to show the yellow color. On a radial longitu- 
dinal section the contrast between the surrounding wall and 
the pit is very marked, the latter looking like a hole in a red 
field. In the final stage the remaining parts are entirely 
yellow, no red being visible. The yellow coloration appears 
first along the medullary rays, and is always in advance of 
the same reaction in the intervening wood cells. Hand in 
hand with the disappearance of the red color goes the 
shrinkage of the secondary lameUa, as described. This 
reaction of the cell-wall is due to the gradual extraction of 
the coniferin elements of the walls. They are at first 
extracted from the innermost lamella, then from the 
secondary lamella, and last of all from the primary 

11 



MISSOURI BOTANICAL. GARDEN. 

lamella and tlie intercellular substance at the angles 
of the cells. If a similar section is treated with chlor- 
iodide of zinc the walls of sound wood cells are col- 
ored yellow-brown. The cells from which the lignin ele- 
ments have been removed stain brown likewise. This 
indicates that they are not cellulose. In this respect the 
disintegration of the cypress wood differs from that caused 
in wood of the yellow pine by Trametes Pini. In the latter 
there is one form of disintegration in which the lignin ele- 
ments are gradually removed from the cell- wall, beginning 
with the secondary lamella, closely followed by the tertiary 
lamella. After this extraction a much thinner wall of pure 
cellulose remains. Some cases were found in wood of 
Pinus ecliinata^ however, which could not be distinguished 
from pecky cypress, i. e., after the extraction of the lignin 
elements, as indicated by phlorogiucin and hydrochloric 
acid, a membrane remains which is not cellulose. Hartig* 
describes a reaction much like the foregoing one in pine 
wood attacked by Merulius lachrymans^ of which he says : 
" It appears as if there were a certain relation between the 
coniferin content of the cell-wall and the ease with which 
the wood is destroyed." This test is so delicate that it 
shows the presence of a disturbing cause in the wood 
long before any evidence can be detected by the micro- 
scope. Other lignin reagents give similar results, although 
not so striking. AniUne sulfate turns sound wood brilhant 
yellow, while it leaves the affected lamellae almost color- 
less. Thallin and phenol give similar reactions. If the 
sections are treated with dilute KOH the normal wood 
cells are not affected beyond very slight swelling. The 
diseased cells swell more or less, particularly those parts 
which stained yellow with phlorogiucin. After prolonged 
action of KOH, the delignified parts stain blue with chlor- 
iodide of zinc. This indicates that the first change in the 



* Hartig, R. Der Schte Hausschwamm 53. Berlin. 1885. 
12 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

cell-wail is the removal of some of the incrustinof sub- 
stances, probably coniferin and vanillin. The KOH re- 
moves the remaining substances and leaves the cellulose 
membrane free to react with chloriodide of zinc. Very 
much rotted wood stains intensely blue after treatment with 
KOH. The blue color appears first about the pits, and 
diffuses towards all sides, looking much like an inkspot on 
which water has been dropped, causing it to diffuse irregu- 
larly over the surrounding area. Sound wood stains yellow- 
brown with chloriodide of zinc, even after treatment with 
KOH, With iodine and sulphuric acid, rotted wood stains 
brown. 

A very different form of disintegration now and then 
occurs (PL 4, fig. 3). What the reason is why one form 
occurs at one time and a second at some other time, I can- 
not explain. Large holes appear in the sound wood, filled 
with a spongy mass of white fibers. The holes have a 
white or tawny lining of fibers, which can be pulled off in 
groups. These holes are as large as the ones filled with 
brown powder. The change in the wood cells is almost 
exactly like that found in pine wood attacked by Trametes 
Pini* above described. The secondary lamella is gradually 
changed so that it stains purple with chloriodide of 
zinc, that is, the lignin substances have been entirely 
removed. Very soon after the first signs of delignification 
become evident, the primary lamella separates into two 
lamellae, which are then dissolved. This causes the indi- 
vidual wood cells, or rather the cellulose fibers, to fall 
apart. No intermediate steps between the hgnified cell- 
wall and the cellulose wall are to be detected, which gives 
the impression that the extraction of the lignin elements 
must take place all at once. The amount of pure cellulose 
fiber thus found in one hole is surprising. From a hole 
3-4 inches long several grams were obtained of many white 



Hartig, R. Zersetzungserscheinungen, etc. 35. 

13 



MISSOURI BOTANICAL GARDEN. 

fibers without any impurities whatever. The quantity of 
wood transformed into cellulose is exceeded only, as far as 
I know, by that found in diseased wood of Juniperus, 
decayed by Trametes Pini, to be described in another 
paper. 

With polarized light, the prisms being crossed, the pri- 
mary lamella of sound wood appears white, i. e.,itis 
highly refractive ; the secondary lamellae are darker. The 
rotted wood, with the exception of some very minute parti- 
cles, allows no light to pass. The hypothesis of a crystal- 
line structure of the cell-wall, as advocated by Niigeli, is 
based largely on its optical properties. Niigeli held that 
the double refraction indicated a condition of stress in more 
than one direction. The absence of any refraction in the 
rotted wood indicates a homogeneous condition, i. e., one 
in which the stress is equal in all directions. The change 
from sound wood to the decayed form must have been a 
profound one to bring about this condition. It has been 
noted for wood destroyed by MeruUus laclirymans* that it 
separates the white polarized light into blue and yellow 
parts. Hartig makes no attempt to explain why this should 
be so. In this connection it may be said that rotted wood 
of Libocedrus decurrens, yet to be described, and wood of 
Juniperus Viginiana destroyed by Polyporus carneuSf 
appear dark when viewed with crossed prisms. 

Humus Compound. 

In the cells immediately surrounding the rotted areas 
certain parts of the walls are colored dark brown by an 
apparently homogeneous substance. This occurs in various 
forms. Most commonly it has numerous cracks and fissures 
breaking it into many plates, looking much like mud which 
has dried in the sun (PI. 4, fig. 4), then again it appears 
in the form of irregular granules scattered along the walls, 



Hartig, R. Der iichte Hausschwamm 61. Berlin. 1885. 
14 



DISEASES OF TAXODIUM AND LIBOCEDRU8. 

usually more numerous at the lower end of the cells. "When 
KOH is added the whole mass dissolves slowly, melt- 
ing away like wax ; the tracheids become filled with the 
red-brown solution. By treating finely divided wood with 
dilute KOH this substance can be extracted in quantity. 
If the potash solution is neutrahzed with dilute HCl, a red- 
brown flocculent gelatinous precipitate is formed slowly, 
which gradually settles to the bottom. When dried it re- 
sumes the appearance seen in the tracheids. In mass it is 
reddish-brown, soft, tasteless and odorless, insoluble in 
alcohol, ether, chloroform, acetone, turpentine, etc., but 
very soluble in alkalies, KOH, NaHPOi, etc., and can be 
reprecipitated from such solutions by acids. Because of 
its peculiar physical and chemical properties the sub- 
stance is classed among the humus compounds. This 
humus compound, as it will be designated, was evi- 
dently at first in a liquid condition, as it fills the cells 
so evenly. Furthermore, wherever mycelium occurs, 
this is coated with a layer of the compound, so that 
the walls of the hyphae look brown and show several con- 
tour-lines. Wherever there is any sign of decomposition, 
there this product appears immediately. It is at first seen 
in the medullary rays, filhng the cells and obscuring their 
contents so that nothing can be distinguished in the cells. 
The brown contents of the rays extend out through many 
annual rings from the initial point of decay. On several 
occasions trees were found with exceptionally large quan- 
tities of this material. In these trees the cavities or holes 
had a brown powdery mass lying loosely within, but the 
bounding walls had a thick coating of the brown substance. 
It was quite soft, broke readily with a shining fracture, was 
non-elastic and dissolved readily in alkalies, in fact agreed 
so closely with substance already found in the tracheids as 
to leave no doubt as to their being one and the same sub- 
stance. The finding was of value as it was possible to 
trace the origin of this compound directly, which was not 

15 



MISSOURI BOTANICAL GARDEN. 

possible in the majority of cases. Our present knowledge 
of the humus compounds is at best a meager one. They 
are generally described * as black bodies, which form in the 
decay of organic substances, and which occur in soil, peat, 
etc. They are divided t into three groups (according to 
their solubilities) : 1. Such as are soluble in alcohol and 
dilute alkahes. 2. Such as are very soluble in alkalies and 
precipitated by acids as gelatinous bodies insoluble in 
alcohol. 3. Such as are very soluble in alkahes, precipi- 
tated by acids, the precipitate soluble in alcohol. The 
substance found in the cypress wood belongs evidently to 
the second class, one to which a large number of products 
belong, particularly those obtained from peat and decaying 
vegetable substances. J 

Much has been written on the humus compounds, particu- 
larly those found in peat. Mulder, §Hoppe-Seyler,|| Griese- 
bach,1[ Senft,** Friih,tt have treated more or less of various 
compounds. Friih gives the best general account and the 
following notes are taken from his paper. He says (p. 
63) : Ulmates and humates, ulmin and humin, ulmic and 
humic acids in homogeneous masses or in fine particles give 
a mass which when moist is slightly elastic. In drying 
these substances contract, become black, shining like glass, 
hard, and break, with conchoidal fracture. The splinters 



* Beilstein, F. Handbuch der organischen Chemie 1 ;1107. 1893. 

t Hoppe-Seyler. Hoppe-Seyler's Zeit. f. phys. Chemie 13 : 1101. 

t Some of the humus compound was seat Dr. Friih who says of it: 
*' It seems to agree in its properties with ulmic acid, or a calcium salt 
of the same." Dr. Van Bemmelen of Leiden has kindly undertaken to 
make a more detailed examination. 

§ Mulder, Liebig's Annalen der Chemie (u. Pharmacie) 36:343. 
1840. 

II Hoppe-Seyler. 1. c. 

1 Griesebach. IJber die Bildung des Torfesin denEmsmooren. Got- 
tingen. 1846. 

** Senft. Die Humus, Marsch und Torfbildungen. Leipzig. 1862. 

tt Friih, J. J. Uber Torf und Dopplerit. Ziirich. 1883. (Gives long 
bibliography.) 
16 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

are yellow-brown at the edges, transparent and soluble in 
5% KOH in the form of the acid or as ulmate or humate; 
humin and ulmin simply swell in 5% KOH. "In the 
humification yellow-brown places appear on the cell mem- 
brane, which can be bleached out with KOH, in the form of 
ulmin or humate ; the remaining cell membrane shows dis- 
tinct cellulose reaction. Lignified membranes ulmify with 
difficulty, although wood cells can change completely into 
peat." Griesebach (1. c.) mentions the transformation of 
wood of Erica Tetralix and Calluna vulgaris into ulmin 
substances. Humic acids have been found in plants, and 
Friih mentions a number of cases. Thus according to 
Lucas, Einhof extracted the same from spores of Agaricus 
atramentarius , while he himself obtained one from Uredo 
segetum. Friih isolated humic acid from spores of Ela- 
phomyces granulatus. 

In the wood of Taxodium in which the large masses of 
humus compound were found the transition from lignin to 
the humus bodies was very evident. PL 3, fig. 2, 
represents a section made through the border of a hole, 
after staining with phloroglucin and HCl. At " g " the 
primary lamella is seen, dark red, indicating the presence 
of coniferin, etc. In the next row of cells the interior is 
coated with yellow-brown masses (h) which in the un- 
stained wood contrast beautifully with the almost white cell- 
wall. These masses are found to be humus substance, 
readily dissolved by dilute KOH. The phloroglucin stains 
the secondary lamella. Between this normally lignified 
portion and the inner humus layer is a layer staining yellow. 
This is evidently similar to the membrane already described 
(PL 3, fig. 1 " d "), i. e. the wood substance gives neither 
a lignin nor a cellulose reaction. After treatment mth 
KOH it stains deep blue. This is in part the process as 
described by Friih, except that here there is an intervening 
step between the hgnin and the humus substance. Pass- 
ing now from the cells just described, one finds the layer 

17 



MISSOURI BOTANICAL GARDEN. 

of humus increasing in width (c). In drying, numerous 
fissures have appeared in the mass. The lignin layer be- 
comes narrower and narrower, then disappears and at last 
even the primary lamella no longer gives the lignin reaction, 
and the whole is transformed into humus compound (e). 
The positions of the original cells are still very evident, 
and here and there a piece (u) of unchanged cell-wall re- 
mains in the homogeneous mass of matter. 

The action of the rotted membranes on polarized light 
has already been mentioned. The primary lamella shows 
decided lis:ht lines in a transection of the kind shown on 
PI. 3, fig. 2, but as soon as the wood no longer gives the 
lignin reaction it appears dark when the Nicol prisms are 
crossed. The same is true of the humus compound. 
Whatever the change is which changes a non-homogeneous 
body to a homogeneous one, it is one which takes place 
when the chemical structure of the non-homogeneous body 
begins to change. When a portion of the humus mass is 
dissolved in dilute KOH there appear in the center of this 
mass certain highly refractive bodies -g— 1^ y"- in diameter, 
of very definite structure resembling human blood corpus- 
cles somewhat (PI. 5, fig. 8). They are hexagonal in 
shape with blunted corners and have a much depressed 
center, so that the edge view shows four contour lines, two 
parallel lines, and two of an hour-glass shape. ' When exam- 
ined with polarized light they shine brightly when viewed 
from the edge, and as they have a decided Brownian 
motion, they alternately flash and disappear. Their very 
variable size, but constant form, as well as their appearance 
in polarized light, suggest that they are crystals of some 
sort. Hartig * says that the comparatively high resistance 
of the walls bounding the lens-shaped pits, is probably due 
to the large number of calcium oxalate crystals imbedded in 
these walls; he indicates these by fine dots (fig. 13). The 



* Hartig, R. Der achte Hausschwamm 57 
18 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

small bodies which he finds he describes as " rounded in 
form." He suggests that they may be crystalline, and 
that the deposition of the Ume in the walls is made in the 
form of crystals. "If this be true it may be asked 
whether the action of the cell-wall when viewed with polar- 
ized light may not be explained by the refraction of these 
bodies." Hartig, however, did not prove the crystalline 
nature of the bodies. The small bodies from the humus 
compound dissolve in HCl, which might indicate them to 
be crystals of calcium oxalate. They are evidently massed 
together in the humus compound, and become visible only 
when the latter is removed. It is not at all improbable 
that they were constituents of the cell-wall, which were not 
destroyed by the disintegrating factor and remained un- 
harmed, imbedded in the liquid mass of humus compound. 
The present data do not warrant any definite conclusions 
as to their real nature and origin. 

From the description just given of the formation of the 
humus compound, and comparing this with the normal 
method of disintegration of the wood, it seems that the 
process may be summed up as follows : For some reason, 
the normal lignified membrane changes, i. e., certain of its 
constituents, which ordinarily react with phloroglucin, are 
extracted. Then more profound changes take place ending 
in the formation of a humus compound. This ordinarily 
diffuses through the adjoining cells, and ultimately hardens 
in the tracheids surroundino; the rotted area and in the medul- 
lary rays. At the same time all contents of the cells, hyphae, 
starch grains, etc. , are covered. Numerous experiments were 
made to determine the approximate per cent, of matter solu- 
ble in dilute KOH, both in much rotted wood and in wood 
immediately surrounding the holes, apparently sound. The 
amounts were found to vary between wide limits. On an 
average about 34% was obtained from much rotted wood, 
the remaining 6Q% consisting of pieces of wood fibres 
not transformed. In the wood immediately surrounding 

19 



MISSOURI BOTANICAL GARDEN. 

the holes 6-8% was obtained. The soluble matter was 
precipitated from the 2% KOH solution with dilute HCl 
and dried at 100° C. 



Wood Between the Rotted Areas. 

The wood between the holes is darker in color than 
the normal wood, but cannot be distinguished from it 
structurally. Numerous fungus threads pass through the 
walls or have punctured them in many places. Near the 
holes much of the humus compound occurs, and many of 
the pits show the peculiar arrangement of oil globules. 
The specific gravity of sound heart wood and that of the 
wood between the holes, was determined by weighing 
blocks and measuring them. As the plates of wood 
between the holes as a rule are but -^-f inch wide, and 
the mass of wood not occupied by holes but -^ inch long, 
the pieces to be measured had to be rather small. To 
bring the two tests under similar conditions, the blocks 
from normal wood were made of similar size. The blocks 
were dried at 100^ C. until approximately constant weight 
was reached. The specific gravity of sound wood was 
found to be .508; that of the other, .401. These figures 
are probably only relatively correct, but as each is the 
average of a number of blocks, they seem to show that 
even if no visible change has taken place in the wood 
between the holes, some change must have occurred, 
otherwise there would not have been so great a difference 
in specific gravity. Very pecky cypress planks which had 
been exposed in lumber yards for many years, were exam- 
ined. The powder and wood fibers which had filled the 
holes had been washed out and had left a smooth, even 
surface. The wood was to all intents and purposes very 
sound, and no change except numerous perforations in the 
walls, and the presence of much humus compound, could 
be detected. 
20 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

It is this property of the pecky cypress not to pass be- 
yond a certain stage of decay, which has made it possible for 
the wood to be utilized in a variety of ways. Dickeson & 
Brown call attention to this fact : ' ' There is this peculiarity 
of this disease, that the cutting do^\Ti of the timber arrests its 
further progress, and timber thus affected, although not as 
strong, is found to last as long as that which is very sound." 
This is probably a unique case of specifically ' < rotten ' ' 
wood still capable of being used for commercial purposes. 
The durability of cypress timber is universally admitted, 
and pecky cypress does not seem to be much less so. 
Where it is, as in this case, a question of dollars and cents, 
the testimony of practical lumbermen is especially valuable. 
Thus, whereas sound cypress lumber sells for $20-$25 per 
1,000 ft. B.M., pecky cypress sells for $5-$10 per 1,000 
ft. B.M. ; generally from $5-$8. One firm makes two 
grades of pecky planks: "pecky," and "dangerously 
pecky ; " " the latter means that the holes are so large 
that a mule might put his foot through"! Mr. G. M. 
Bowie, of Whitecastle, La., writes: " I am watching some 
pecky planks laid on the ground, exposed to rain and sun; 
they are unchanged so far in ten years." Throughout the 
Southern States pecky cypress boards are used for bridge 
planking on plantations, for siding, sidewalks, flooring, 
culverts, foundations under brick work, in wet places, etc. 
Mr. A. S. Mohr, of Apalachicola, Fla., says: " We use 
pecky planks 2 in. thick and upwards for making drive- 
ways, wharfs, tramways, and for such purposes it is in- 
valuable." 

In Mobile, for instance, where there are open ditches along 
many streets, the vertical bank, flanking the pavement, 
and the bottom of the ditch are lined with pecky boards, 
and their lasting powers seem to be fully equal to sound 
boards. (PI. 6.^ 

For sidewalks, such lumber is used in almost every town 
or city within the reach of cypress swamps, and when the 

21 



MISSOURI BOTANICAL GARDEN. 

softer powder has worn away the grooved boards have a 
singular appearance. 

From such data it may safely be said that the disintegra- 
tion never goes beyond a certain stage. When a tree is 
cut down the further progress of the disease is stopped. 
No tree, as far as is known, has been seen in which all the 
wood had been destroyed, and it is for this reason that a 
diseased tree remains standing even when much decayed. 



Strength of Cypress Wood. 

A number of tests were made to determine the relative 
crushing strength of sound cypress wood and that of ver}'^ 
pecky wood.* In making these tests blocks cut from the 
heartwood were used. These were dried in a kiln for three 
days and were tested immediately after being taken from 
the drying oven. The tests were made with the machinery 
used for the timber tests of the U. S. Division of Forestry. f 
A full description of the same will be found in the bulletin 
referred to. 



Crushing Strength (Endwise), of Sound Cypress. (Heartwood.) 



6 


Dimen- 
sions of 
block. 
Inches. 


Height. 
Inches. 


Area. 
Square 
inches. 


Breaking 

load. 
Pounds. 


Breaking 

load per 

square 

inch. 

Pounds. 


Locality. 


1 
2 
3 


1.32X1.30 
1.69X1-27 
1.55X1.29 


3.24 
3.23 
3.00 


1.71 
2.14 
1.99 


12,300 
16,490 
14,250 


7,191 
7,144 
7,160 


From Lutcher, La. 
({ (I (( 



* In making these tests I am much indebted to Mr. W. H. Henby for 
material assistance. 

t Timber physics. Pt. I. (Bull. U. S. Div. of Forestry 6: 31.) 
Washington. 1892. 
22 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 
Crushing Strength (Endwise), of Pecky Cypress. (Heartwood.) 



d 
15 


Dimen- 
sions. 
Inches. 


Height. 
Inches. 


Area. 

Sq. 

inches 


Breaking 

load. 
Pounds. 


Breaking 
load per 

square 

inch. 
Pounds. 


Character. 


1 
2 

8 

4 
5 


2.13X3.25 
2.66X3.17 

2.92X3.16 

3.25X3.37 
3.47X3.52 


5.98 

6.87 

6.86 

6.65 

7.75 


7.14 
8.40 

9.23 

10.95 
12.21 


35,170 
43,680 

40,130 

56,050 
40,850 


4,925 
5,200 

4,350 

5,120 
3,345 


A little sapwood 
in one corner. Up- 
per surface showed 
4 pecky spots. 

Near center of 
tree, 14 holes visible 
on upper surface. 

Very pecky. 14-18 
holes visible on up- 
per and lower sur- 
faces. 

Very pecky. Same 
appearance as No. 3. 

Extremely pecky. 



Crushing Strength (Endwise), of Pecky Cypress Before 
Drying. (Heartwood.) 



d 


Dimen- 
sions. 
Inches. 


Height. 
Inches. 


Area. 

Sq. 

inches 


Breaking 

load. 
Pounds. 


Breaking 
load per 
sq. inch. 
Pounds. 


Weight 
moist 
Grams. 


Weight 

dry. 
Grams. 


% 
Moist- 
ure. 


1 
2 
3 


3.03X3.22 
3.30X3.44 
3.51X3.55 


4.37 
3.06 
3.29 


9.75 
11.35 
12.46 


30,200 
35,680 
35,970 


3,097 
3,143 
2,886 


335 
275 

287 


278 
238 
261 


17.0 

13.6 

9.0 



In these tables but a few tests are given : a more exten- 
sive list is in preparation. A glance at these tables will 
show how comparatively strong the very pecky wood is, 
which is a rather surprising feature. It is of course diffi- 

23 



MISSOURI BOTANICAL GARDEN. 

cult to state exactly liow pecky a certain piece is, but the 
samples tested were considered as fair averages of the grade 
generally used for sidewalks, etc. The block marked 5 
was very much more pecky than the others. From the 
third table it appears that when wet the wood is less strong 
than when thoroughly dry, which is true of all woods. 
The breaking of the pecky blocks was almost without ref- 
erence to the holes. The wood between the holes had to 
stand the load, and that it was capable of holding up as 
much as it did is another proof of its comparative sound- 
ness. The number of tests made so far is as yet too small 
to determine whether any relation exists between the abso- 
lute weight of wood fiber present in the pecky logs and the 
breaking strength. 

Mycelium. 

Within the holes, and throughout the heartwood of a dis- 
eased tree, the mycelium of some fungus is constantly met 
with. This is present but sparingly, and rarely forms ex- 
tended masses or felts. In spite of extensive and search- 
ing examinations of a very large number of cypress trees 
for several years, no fruiting organ has yet been met with. 
The only fungus ever reported was the one mentioned by 
Sargent * which, as far as can be determined now, had 
little adequate foundation. Of the other fungi hitherto 
reported as growing on Taxodium none could be brought 
into any causal connection with the mycelium always found 
in the tree. It is to be hoped that before long the fruiting 
form may be discovered. 

The disintegration of the wood is, in many respects, like 
that brought about by Trametes Pini^ but so far there is 
no evidence to prove that this is the fungus which causes 
the " peckiness." 

Wherever there is any sign of decay in the cypress wood, 



* Sargent, C. S. Forest trees of N. A. 10th Census 9 : 184. 
24 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

a distinct mycelium is present, and the probabilities are 
strong that it is the one which brings about the decay of 
the wood. The hyphae are brownish when young, but 
soon become colorless. Their chief and striking characteristic 
is the presence of very many clamp connections (PI. 5, fig. 
1). Brefeld,* Hartig,t and others have shown that these 
organs are to be found among the Basidiomycetes, particu- 
larly among the Agaricineae and Pohjporei. Brefeld (I.e.) 
describes their formation in Ooprinus stercorarius as lateral 
outgrowths of one cell fusing with the cell beneath it, and 
then forming a separating wall. At such points numerous 
branches usually appeared. Hartig (1. c.) describes the 
clamp connections of MeruUus lachrymans. In this fungus 
they bud out, and form a branch, sometimes before the 
separating wall in the clamp has fused with the next cell. 
This is a unique case among the Hymenomycetes, as the 
clamps are " sterile " in all other forms. 

The clamp connections occur on all parts of the mycelium 
found in Taxodium^ but in no case did any of them branch 
as they do in MeruUus. The mycelium consists of large 
hyphae with distinct thin walls, and hyphae of smaller diame- 
ter. The larger hyphae are constricted at the points where 
two cells join. They branch frequently, giving rise to the 
hyphae of smaller diameter. These in turn branch and 
rebranch. At certain points a short branch is given off 
which divides very rapidly into the finest threads, of hair- 
like dimensions. These smaller hyphae penetrate the cell- 
walls in all directions. Connections between adjacent 
hyphae occur frequently, also compKcated masses, where 
large numbers of hyphae have fused more or less. As a 
rule there is but very little mycelium to be found either 
in the much rotted wood or the intermediate parts. Nu- 
merous holes occur all through the wood, indicating where 



* Brefeld, 0. Untersuchungen iiber Schimmelpiize 3:16. 1877. 
t Hartig, R. Der achte Hausschwamm 14. pi. 1, fig. 3. 

25 



MISSOURI BOTANICAL GARDEN. 

the hyphae had passed through the walls. The threads 
show no preference for the pits. The holes often have the 
shape of a figure 8, i. e. they enlarge within the secondary 
lamella, a feature which is common to wood destroyed by 
many wood-destroying fungi. The scarcity of mycehum is 
striking, resembling in this respect wood in which Poly- 
porus sulphureus has been growing.* In branches where 
the disease is in its youngest stage, the mycelium occurs 
more plentifully in those areas, which correspond to the 
holes to be formed later on. Between these areas the 
hyphae pass, boring through the tangential walls. 

Besides the colorless mycelium, a mycelium is often 
present in the wood between the decayed holes. This 
appears to belong to some saprophyte, which has nothing 
to do with the original decomposition. This mycehum is 
composed of brown threads which pass through the tan- 
gential walls preferably and follow the direction of the 
tracheids up and down. These hyphae form marked at- 
tachment organs when boring through the cell-walls. Frankf 
described such organs as formed by the germ tubes of Fusi- 
cladium tremulae. The hypha when it touches the epidermis 
forms a swelling with one or more pores, from which fine 
tubes push through the walls into the epidermal cells. He 
called the swollen parts ' ' Appressorien ' ' or attachment 
oro-ans, and beUeved that they aided the hypha in punctur- 
ino- the wall. De Bary | found similar organs in germ tubes 
of Peziza Sclerotiorum ; these were formed ' ' owing to a 
mechanical stimulus, which the resistance of a solid body 
exerts on the hyphal branches." Biisgen § described the 



* Hartig, E. Zersetzungserscheinungen des Holzes 110. 

t Frank, B. Uber einige neue u. weniger bekannte Pflanzenkrank- 
heiten. (Ber. d. deut. bot. Ges. 1 : 30. 1883.) 

X De Bary, A. Uber einige Sclerotinien u. Sclerotienkrankheiten. 
(Bot. Zeit. 44:377. 1886.) 

§ Biisgen, M. Uber einige Eigenschaf ten der Keimlingeparasitische 
Pilze. CBot. Zg. 51 : 53, 1893.) 
26 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

attachment organs as smaller portions of a hypha, formed 
as a result of contact or pressure irritation. " These 
organs adhere very closely to the cell-walls and in that way 
probably act as braces to give the penetrating hypha an 
opportunity to exert the mechanical pressure necessary to 
penetrate the cell-wall." Miyoshi * found that in order to 
penetrate a wall ' ' the fixation of the hypha was absolutely 
essential ' ' and explains the formation of attachment organs 
as tending in that direction. Hartig f figures several cases 
of swollen hyphae in the mycelium of Polyporus vapo- 
rarius. 

The penetration of the cell-wall is brought about, accord- 
ing to Brefeld,$ Biisgen (1. c), Miyoshi (1. c), Ward, § 
and others by the chemical action of a ferment given off by 
the tip of the hypha, aided by pressure. In the diseased 
wood of Taxodium the brown hyphae pass through the 
cell-walls of the wood fibers of both spring and summer 
wood in a radial direction. The path of a hypha is made 
up of a succession of short curves, each within the lumen 
of a wood cell (PI. 4, fig. 1). When the tip of a hypha 
touches the wall it is deflected considerably, as if the hypha 
were pressing against the wall and pushing along the same. 
At the same time the tip swells, and a thread of much 
smaller diameter pushes into the wall. Sometimes there 
may be two such threads (PI. 5, fig. 9). When they 
have passed through the wall they enlarge to the former 
size of the hypha, and grow on through the next cell, to 
be deflected as before upon reaching the opposite wall. 
On PI. 5, fig. 9, a number of these attachment organs are 
represented, occurring in the wood of Taxodium, and also 



* Miyoshi, Manabu. Die Durchbohrung von Membranen durch 
PilzfMen. (Prings., Jahrb. f. wiss. Bot. 28:269. 1895).— ijber Che- 
motropismus der Pilze. (Bot. Zg. 52 ; 1. 1894.) 

t Hartig, R. Zersetzungserscheinungen, eic.pl. 8. fig. 11. 

X Brefeld, O. Untersuchungen iiber Schimmelpilze 4: 112./. 11, 15. 

§ Marshall- Ward, H. On a lily disease. (Ann. Botany 2 : 319. 1889.) 

27 



MISSOURI BOTANICAL GARDEN. 

in diseased wood of Libocedrus decurrens. At a one of 
the attachment organs has formed a branch. These organs 
adhere very firmly to the walls against which they are 
pressed ; from the curved form of the hypha one is led to 
suppose that the pressure exerted by the hypha must be 
considerable. The reason for supposing these brown 
hyphae to be saprophytic is that they are usually found 
somewhere in the wood near a knot hole, where there is 
abundant opportunity for the entrance of saprophytes. 

In many cases a form of mycelium with very thick walls 
occurs. This has few clamp connections and forms thick 
felts in the holes. This was found only in logs after they 
had been cut, so there is some reason for considering it as 
foreign to the disease. The great age of many of the cypress 
trees, and the consequent presence of numerous places where 
branches have been broken off, allows many fungi to get in 
which live on the dead and decaying wood, but which seem to 
have nothing to do with the peckiness. Their presence makes 
the study a difficult one at times, especially as they seem to 
grow rapidly and fructify readily. Thus a number of spore 
forms were met with, but in no case could these be brought 
into any connection with the colorless mycelium. One 
form was found very often (PI. 5, fig. 5) also frequently 
present in diseased wood of Libocedrus decurrens and Juni- 
perus Virginiana. The spores are almost round, about 
\ fx in diameter, brown, with a distinct wall and a central 
shining body which is not affected by reagents. Many of 
the spores have short knobs. The spores occur in such 
numbers in the wood around the holes that it seems proba- 
ble that they were formed in chains and may be considered 
chlamydospores. A number of times chains of two or 
three were found with fine remnants of hyphae attached. 
These spores were placed in cultures of dung, cypress agar, 
and gelatin, but have so far refused to germinate. It is 
possible that they represent some form of entophytic 
organism (^Chytridiaceae 9 Phytomyxae?) studied by 
28 



DISEASES OF TAX0DIU3I AND LIBQCEDKUS. 

Fischer, Dangeard, De Wildeman and others. Brefeld * 
records an instance of similar spores in Peziza tiibe- 
rosa. These were constricted off in chains and refused 
to germinate. Hartig f found spores in wood destroyed by 
Pohjporus sulphureus. These, he says, belong to some 
saprophytic fungus, always found with Polyporus sulphur- 
eus. In wood of Quercus alba and Q. nigra destroj^ed by 
Polyporus sulphureus, collected in New York and Arkansas, 
similar spores were found, represented on PL 5, fig. 8, for 
comparison. They seem to be constantly present wherever 
Polyporus sulphureus has destroyed oak wood. The asso- 
ciation of these two fungi is not understood as yet, and 
awaits further investigation. 

Besides the brown spores a number of others occur, a 
few of which may be mentioned. One form, large, black 
spores in chains, resembles Willkomm's % Xenodochus ligni- 
perda (PI. 5, fig. 7). Another form, consisting of large 
two-celled chlamydospores (PI. 5, fig. 4), is not infre- 
quent. 

Progress of the Disease. 

In the early stages of the disease the wood turns yellow 
in localized areas, about \ inch wide and extending longi- 
tudinally with the wood fibers" for several inches (PI. 1, 
fig. 1). These areas are separated by intervening layers 
of wood, unchanged in color. In the wood cells of the 
yellow areas numerous hyphae of the colorless mycelium 
are found. The larger hyphae extend longitudinally 
through the cells and give off many branches which pass 
and repass through the walls. The ultimate hairlike 
branches reach every cell in the area. Numerous clamp 
connections are to be seen. Between the yellow areas the 
hyphae extend through the wood cells, passing through the 



* Brefeld, O. Bot. Untersuchungen iiber Schimmelpilze 4 : 113. 
t Hartig, R. Zersetzungserscheinungen, etc. 113. pi. 14. f. 10-12. 
X Willkomm, M. Die mikroscopischen Feinde des Waldes. pi. II. 
f. 8. 1866. 

29 



MISSOURI BOTANICAL GARDEN. 

walls radially to another yellow area at that height or longi- 
tudinally to one above. Immediately around the yellow 
areas it looks as if the hyphae were passing through this 
wood as rapidly as possible. As the disease progresses the 
mycehum can be found only sparingly in the yellow areas 
and in the surrounding wood. Their former presence is 
indicated by the numerous holes in the walls. 

From the facts presented, it seems that the growth of 
the fungus is about as follows : The mycelium starts at 
some point in the heart-wood where it flourishes in a limited 
area for some time. Some of the threads then grow out 
from this area (which is limited, for some reason or other), 
and grow both transversely and longitudinally from the 
original center. At points some distance from this center 
new centers are established, which in time are limited 
and form starting-points for further growth. One may 
cut through a young branch and find the cut surface per- 
fectly sound. On splitting both pieces of the branch, one 
may find that at points several inches above the cut one or 
more distinct yellow areas are present, and the same may 
be true of the piece below the cut. In the wood between, 
numerous hyphae occur, which, however, do not spread in 
this wood. The areas where vigorous development has 
taken place ultimately become holes, and the tree then 
appears as already described, i. e., sound wood fiUed 
with lens-shaped cavities. The original hyphae are gradu- 
ally absorbed, so that after a time the figure-8 holes in the 
walls are the only evidence of their former presence. 

The path of the mycelium is always the shortest distance 
from hole to hole. This apparent avoidance of the wood 
between holes — an apparent preservation — is very strik- 
ing. It is suggested that this is probably due to chemical 
influences which affect the hyphae in this manner. All 
attempts to grow the mycelium have so far failed. Media 
were prepared from decoctions of cypress wood and care- 
fully titrated ; they were then inoculated with fresh myce- 
30 



DISEASES OF TAXQDIUM AND LIBOCEDRUS. 

lium, which, however, did not grow. Fresh pecky wood 
has been kept in moist chambers now for almost three 
years without any sign of growth. Further experiments 
are in progress. 

Propagation op Disease. 

The constant presence of the colorless mycelium in dis- 
eased trees makes it seem probable that this is the vegetative 
part of a fungus which causes the decay. As has been 
said, no fruiting organ has yet been found, so the manner 
in which this disease is carried from tree to tree is still to 
be discovered. A large number of logs were spUt open, 
and in some of these, large places were occasionally met with 
where an old branch had been healed over, leaving a cavity. 
In this cavity dense white felts of the mycelium, in which 
numerous crystals of calcium oxalate were imbedded, were 
obtained. There was, however, no sign of a fruiting 
organ. In some boards beginnings of such felts were found 
but none of these have developed any further. Reasoning 
by analogy from the diseases of trees already known we 
ought to find at some time a pileus of some sort. That 
infection takes place through a broken branch or some 
part of the top of the tree is most probable. Many trees 
were cut down in which the ' ' peck ' ' could be traced 
directly to a broken branch, extending up and down from 
this point. This was especially marked where, as in a 
number of instances, the " peck " was confined to one side 
of a tree. 

Localization of Disease. 

The most characteristic feature in connection with this 
disease, distinguishing it from others so far described, is 
its peculiar localization, i. e., the destruction of the wood 
in distinctly locahzed areas. The formation of the holes 
has been described, and it has been noted that the contrast 
between diseased areas and sound wood is a marked one, 

31 



MISSOURI BOTANICAL, GARDEN. 

furthermore that fungus threads occur all through a given 
section of a tree. 

The manner in which fungi influence their hosts varies 
considerably. One may consider the distribution of the 
mycehum within the host. There are but few references 
to this point in discussions on fungi. Tubeuf * says ; 
' ' A large number of fungi have a mycelium which never 
extends beyond a very short distance round the point of first 
infection, and cause only local disease, frequently with no 
perceptible disturbing effect on the host. Such is the case 
with leaf spot diseases." Thus Frank f describes the 
mycelium of Gloeosporimn Lindemuthianiiin as caus- 
ing a browning of the tissues as far as the mycelium 
extends. The same is true of Oercospora. The mycelium 
of Aecidium Uliamni on Rhamnus frangula has a 
local distribution, t so also that of many Erysipheae, 
for instance Microsphaera densissima also Uncinula necator 
of which an interesting case was recently described by 
Stevens. § This localization of the mycelium may be due 
to mechanical obstructions, such as the veins of a leaf, as in 
JPuccinia Podophylli, or to chemical reaction on the part 
of the host. The large majority of fungi have a mycelium 
which extends through large areas of their hosts . Wakker 
(1. 0.) classifies parasitic fungi according to their effects on 
their hosts as producing either mechanical or chemical 
effects. By mechanical effects he understands such as are 
due to direct pressure. The vast majority affect their 
hosts chemically. Here again two classes may be distin- 
guished, such as produce chemical effects " which will im- 
mediately, or otherwise exert a direct destructive influence 



* Tubeuf, C. Freiherr von. Diseases of plants 16. (Eng, edit.) 

t Frank, B. IJber einige neue u. weniger bekannte Pflanzenkrank- 
beiten. (Ber. d. deut. bot. Ges. 1 : 31. 1883.) 

X Wakker, J. H. Untersuchungen iiber den Einfluss parasitischer 
Pilze auf iiire NShrpflanzen. (Prings., Jalirb. f . w. Bot. 24 : 505. 1892.) 

§ Stevens, F. L. A peculiar case of spore distribution. (Bot. Gaz. 
27:138. 1899.) 

32 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

on their hosts and those which hve for a longer or shorter 
period with their host without producing such effect."* 
To the first class belong all such plants as produce imme- 
diate death, like Pei'onospora, Agaricus melleus and many 
Polyporei, and those producing hypertrophies, such as 
Gymnosporangium, Exoascus, and others. To the second 
class belong many UredineaeQud. Usfilagineae, JExobasidium^ 
etc. In the latter cases the mycelium may live for a long 
period in the cells without any perceptible effect on them. 
The reason for this "conservation" (Tubeuf, 1. c.) is 
doubtless to be sought in complex chemical conditions which 
brinof about one kind of effect with one, and another with a 
different fungus. 

In aU the cases just mentioned, one is dealing with living 
tissues capable of reaction of some sort. This reaction 
may take the form of starch accumulation, hypertrophied 
structures or the formation of products antagonistic to the 
growth of the invading fungus. The bacteria are a good 
example of organisms bringing about the last form of reac- 
tion, i. e., where the host produces substances which 
neutralize the poisonous products formed by the parasite. 
To what extent similar processes take place in plant cells is 
yet unknown, but there seems to be no reason Avhy they 
should not. 

In the heartwood of a tree one is dealing with a plant 
member to all intents and purposes dead, i. e., its power to 
react to any stimulus has been lost, so that such influences 
as would affect the distribution as well as chemical activi- 
ties of a mycelium in a living member can have no bearing 
here. Ther6 is in the Taxodium a marked localization, 
and, as wiU be shown, this is also present in Lihocedrus 
decurrenSf Juniperus Virgimana, J. Bermudiensis, and to 
some extent in pines attacked by several of the Polyporei. 

The localization of chemical action, for such the disinte- 



* Tubeuf, C. Freiherr von. Diseases of plants 21. 

33 



MISSOURI BOTANICAL GARDEN. 

grating action on wood must be, cannot be due to mechan- 
ical causes, sucli as difference in the character of the wood 
cells, or the presence of obstructing layers. In the first 
place all wood cells are disintegrated, whether they be of 
the spring or summer wood, and the bounding lines of a 
cavity are not influenced by the harder summer wood as 
might be supposed. Then again no resistant layers, as 
such, excepting the harder summer wood, exist in the heart- 
wood. The isolated resin cells seem to have no bearing in 
this connection. The only remaining explanation is to 
attribute the local decay to chemical influences, which pre- 
vent the decay from spreading beyond well-defined limits. 
It is a well-known fact that certain kinds of wood are 
more durable, i. e., resist the destructive influences of fungi 
longer than others. Willows, for instance, are more 
easily destroyed than oaks or cedar. Frank * and Temme f 
have shown that in dicotyledonous trees a certain preserv- 
ative gum is found. This is formed in aU wounds open 
to the air, and occurs normally in all heartwood. This 
wound gum fills the vessels similarly to thylloses, and ren- 
ders them impassable to air and water. The wound gum 
is insoluble in alcohol, ether, H2SO4, KOH, but soluble in 
hot IINO3. These authors do not explain what causes the 
formation of this preservative material, beyond the fact 
that it forms when healthy wood is wounded and exposed 
to the air. In the Coniferae this substance is not present 
and Frank t holds that the infiltration of resin takes the 
place of the gum. Hartig § finds a yellowish-brown mass 
in the ceUs adjacent to wounds in trees. This mass is 
usually much cracked. He caUs it dried brown solution, 



* Frank, B. iJber die Gummibildung im Holze u. deren physiologische 
Bedeutung. (Ber d. deut, bot. Ges. 18 Juli, 1884). 

t Temme, F. Uber Schutz und Kernholz, seine Bildung u. seine phy- 
siologisclie Bedeutung. (Landw. Jahrb. 14: 465. Taf. 6, 7. 1885. 

I Frank, B. Die Krankheiten der Pflanzen 1 : 41. 1895. 

§ Hartig, R. Zersetzungserscheiuungeu etc. 66. pi. 11. fig. 7. 

34 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

and believes that it consists of decomposition products of 
wood exposed to the disintegrating influences of the outer 
air. These products are dissolved by water and penetrate 
far into the tree, bringing about the characteristic phe- 
nomena of wound rot. Frank * claims that Hartie: has 
mistaken the nature of this substance, which he says is not 
a humus compound but wound gum, which acts as a pre- 
servative. A comparison of Hartig's figure and the one 
on PI. 4, fig. 4, will show that in point of appearance the 
substance described by Hartig and the one in Taxodium 
cells are ahke. I have also found such substances in 
wounds, and neither these nor the substance in Taxodium 
are the wood gum which Frank describes. I beheve that 
Hartig is right when he calls them humus solution, but 
cannot agree that they are active in promoting decomposi- 
tion. It might be added that Willkomm f ascribes the 
brown coloration of diseased pine wood to a humus com- 
pound which he says is formed from the cell-walls when 
they begin to decompose. 

No substance corresponding to Frank's wound gum could 
be obtained from the Taxodium. An aqueous extract of the 
sound wood is yellowish in color, due to some coloring 
matter akin to curcumin. A number of analyses made 
of diseased wood failed to give any substances which might 
be regarded as preservative. The sole difference so far found 
between the normal wood and the diseased wood was the 
constant presence of the humus compounds described in 
the diseased wood. 

There are numerous instances which illustrate the preserva- 
tive and antiseptic properties of humus compounds. The 
preservative powers of peat deposits are well known. Peat 
is largely if not entirely composed of humus compounds of 
one kind or another. Its preservative and antiseptic prop- 



* Frank, B. Krankheiten der Pflanzen 1 :32. 1895. 
t Die mikroscopischen Feinde des Waldes 68. 

35 



MISSOURI BOTANICAL GARDEN. 

erties have been attributed to its humus acids. Thus 
Stutzer and Burri * killed cholera germs in a quarter of an 
hour with a decoction of peat. Lyell t speaks of the re- 
mains of animals and men, which had been perfectly pre- 
served for many years in peat bogs. Kerner von Marilaun | 
holds that the preservation of plant parts is brought about 
in moors by humus acids. " The dead plants are saturated 
with these acids and are not resolved into carbon dioxide, 
ammonia and water, but preserve their form and weight. 
The rapidity of decay varies inversely as the quantity 
of compounds of humus acids present." Also " the fact 
that fossil remains of Equisetums, Lycopodiums and 
Cycads . . . have reached us in such good condition, 
is explained by the presence of humus acids which are 
found so universally in peat.§ Ganong I| points out that 
the scarcity of nitrogen in peat bogs is due to the absence of 
bacteria ' ' caused doubtless by an actively antiseptic quality 
of the bog water." Trees and stumps have often been 
found in bogs perfectly preserved. Lyell (1. c.) speaks of 
tree-trunks dug out of Irish bogs and used for masts, also 
of white cedar logs in New England bogs. % Other 
instances might be mentioned, but these will suffice to 
show that the humus compounds have antiseptic and 
preservative properties. 

In the heartwood of the cypress one finds the wood 
substance being spht up and destroyed. The decomposi- 
tion stops after a time, and the fungus mycehum, which at 



* stutzer A., u R. Burri. Uutersuchungen iiber die Einwirkung von 
Torfmull . . . auf die Abtotung der Cholerabakterien. (Zeits. i. Hyg. 
u. Inf. Krank. 14 : 453. 1893.) 

t Lyell, Sir Chas. Principles of geology 722. 

t Kerner von Marilaun, A. The natural history of plants 1 : 262 (Eug, 
edit, by F. W. Oliver). 1894. 

§ Kerner von Marilaun. 1. c. 2 : 612. 

II Ganong, W. F. Upon raised peat bogs in the province of New 
Brunswick. (Trans. Koy. Soc. Canada ii. 3 : 131. 1897.) 

f Lyell, Sir Chas. A second visit to the United States 33. 1850. 

36 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

first developed profusely, evidently stops growing. The 
threads become coated with a brown substance, which also 
fills many of the cells around the area where active decom- 
position has taken place, and saturates the cell walls. 
This humus substance is one of a class knowTi to possess 
antiseptic properties. These facts suggest that the humus 
compound described above may in part be the agent which 
limits the disintegrating effects of the fungus. 

Origin op the Humus Compound. 

The origin of the humus compounds is still a matter of 
some uncertainty, owing to the intrinsic difficulties. Friih, 
who probably has paid more attention to this problem than 
any other investigator, says that we know as little about the 
successive stages which a plant member passes through, 
until peat is formed, as we do of the processes which bring 
about these changes.* The process is essentially a process 
of decay. It is at present recognized that decay may be 
due to chemical processes as such, distinguished from those 
brought about through the agency of living things. 
Where decay, or more properly ar splitting up of highly 
complex organic compounds into simpler compounds such 
as carbon dioxide, ammonia and water, takes place without 
the aid of bacteria or fungi, it is largely a process of oxida- 
tion. If access of oxygen is prevented no decay takes 
place. Hartig,t speaks of the decomposition of plant 
members following death due to frost, as a process due to 
the action of oxygen on the dead organic substance ; fungus 
mycelia get into the tissues after a time and hasten this de- 
composition. Friih| distinguishes two forms of decomposi- 
tion not due to chemical changes per se (such as oxidation) ; 
these he calls " Gahrung " and <' Fermententwicklung." 



* Fruh, J. J. Uber Torf u. Dopplerit 38. 

t Hartig, R. Zersetzungserscheinungen, etc. 65. 

J Friih, J. J. 1. c. 39. 

37 



MISSOURI BOTANICAL GARDEN. 

The first process is brought about ' ' through the direct in- 
fluence of the plasma of a living fungus, and is characterized 
by an evolution of heat and carbon dioxide. The other form is 
caused by a ferment excreted by living plants. This distinc- 
tion can no longer be made to-day, as it seems probable that 
the first form of decomposition is also due to a ferment. 
Since humification takes place only under water, Friih holds 
that one might suppose a ferment the active agent in the for- 
mation of peat. But this cannot be true, for, if a ferment 
were the agent forming peat from vegetable substances, the 
jDrocess of humification would be a uniform one, that is, a 
given mass would be entirely transformed into peat. In a 
bog, however, this is not the case, for there are alternate 
layers, some of which are humified, others not. Friih, 
therefore, agrees with Eiuhof who says that " lack of free 
oxygen, a high degree of moisture and a low temperature, 
brought about by much moisture, bring about a decompo- 
sition of a peculiar kind, i. e., the formation of humus 
compounds or peat." He sums up as follows:* "The 
formation of peat is neither due to ' Gahrung ' nor to a fer- 
ment but consists in the slow decomposition of plants, with 
the greatest possible exclusion of oxygen by water, and at 
low temperature. Bacteria have nothing to do with the 
formation of peat." This view of peat formation is the 
one generally accepted; thus, Shaler f explains it as 
due to the arrest of disintegration arising from the fact 
that the oxygen of the air does not have free contact with 
the carbon, and thus cannot convert it into CO2. 

This explanation practically states the fact that cellulose 
and lignin do change into a series of humus compounds, 
and that it is a process of chemical change. It does not 
explain what that change is and why it should take place. 



* Friih. 1. c, 49. 

t Shaler, N. S. Peat deposits. (16th Rep. Director U. S. Geol. 
Survey. 4:308. 1895.) 

38 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

A number of observers still maintain that fungi or bacteria 
are active in bringing about humification. Thus Hoveler * 
finds that in the humus of a forest the mycelia of fungi 
initiate the process of humification. These mycelia are 
brown in color and are found in every humus soil. They 
belong to many different fungi and are characterized by 
possessing clamp connections. Cladosporium humifaciens 
Rostrop, he regards as the form most frequently present. 
In decaying trees, and in such as are attacked by various 
fungi, such humus compounds are frequently present ; they 
have been classed as decomposition products without fur- 
ther statement as to their origin. In decaying masses 
numerous fungi usually grow all through the mass, which 
makes it difficult to decide what the true humifying agent 
is. In the cypress a humus compound usually appears 
in the cells in which a definite fungus mycelium is grow- 
ing. The same is true and probably more marked where 
the mycelium of Trametes Pini grows in pine wood. The 
latter turns red-brown very soon after the mycelium has 
entered the wood, and examination shows that this color is 
due to a humus compound. No humus compound is pres- 
ent in sound wood. This behavior of the compound 
makes it seem probable that the fungus in some way changes 
the cell-walls, and that the humus compound is one of the 
direct products of this change. 

Ferments. 

In the decomposition of wood it has been assumed that 
ferments take an active part. Enzymes which attack cellu- 
lose and lignified membranes are known. De Bary f and 



* Hoveler, W. Uber die Verwerthuug des Humus bei der Erniihrung 
der chlorophyll-fiihrendea Pflanzen. (Prings., Jahrb. fiir wiss. Bot. 
24 : 290. 1892.) 

t De Bary, A. ijber einige Sclerotinien und Sclerotienkrankheiten. 
(Bot. Zg. 44:377. 1886.) 

39 



MISSOURI BOTANICAL GARDEN. 

Marshall- Ward * isolated ferments which corroded cellulose 
membranes. Brown and Morris f discovered a ferment 
in germinating barley grains, and Vignal | records a case 
of a ferment secreted by Bacillus 7nesentericus , disso- 
ciating vegetable cells by destroying the middle lamella. 
The action of the wood-destroying fungi is such, that 
Hartig and others have attributed the decay which 
they bring about to some enzyme excreted by the 
hyphae. That the same fungus produces several such 
enzymes must follow from the different effects which the 
same fungus has on the same wood. If then we assume 
such a cytohydrolytic enzyme to be formed by the Taxo- 
dium fungus, we find it destroying the wood about a certain 
center. As the mycelium grows along the vessels more 
readily than across them, a long hole is formed. As 
a result of the action of the fungus on the cell-walls, an 
acid humus compound is formed, which is deposited in the 
cells surrounding the center of fungus activity. It is not 
far to make the further assumption that after a time the 
amount of humus compound would be sufficiently great to 
stop the further development of the fungus in that area. 
The hyphae however pass through this area to a new center, 
where they begin over again. This would explain why the 
holes are approximately of the same size. The amount of 
antiseptic substance necessary to prevent further decompo- 
sition would be about the same in each area, and it would 
require the decomposition of a definite amount of wood to 
form this quantity. It may be objected that the holes are 
not always bounded by solid wood, but often run together. 
This would be explained by supposing the amount of 
humus formed at that point not sufficient to overcome the 
influence of the enzyme. 

The conditions under which enzymes are active are 

* Marshall-Ward, H. On a lily disease. (Ann. Bot. 2 : 346. 1888.) 
t Brown and Morris. Jour, of Chem. Soc. 57 : 505. June, 1890. 
X Vignal. Cont. a I'^tude des bact^riacles. (Th§se. Paris.) 
40 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

variable. Marshall -Ward * finds that in a distinctly alkaline 
liquid the mycelium of Botrytis will no longer grow. The 
enzymes of most bacteria are effective only in alkaline 
or neutral media f while those of many fungi are active 
in distinctly acid media although growth is more vigorous in 
neutral solutions, t Green § notes ' ' the possible significance 
of the inhibitory effects of traces of acid or alkali in the 
solution in which the enzyme is working," and Smith |1 has 
made similar observations. It is suggested that the humus 
compound may, because of its acidity, bring about condi- 
tions unfavorable to the activity of the enzyme formed in 
the cypress wood. As the humus compound is at first in 
liquid form, it saturates the wood cells for some distance 
around the hole, and thus completely fills the space where 
the mycelium is growing and many of the cells outside of 
this space. This explains why the hyphae as a rule grow 
out from the holes in straight lines without branching much 
in the wood surrounding the holes. 

The enzymes are usually soluble in cold water, and can 
be precipitated from a solution by an excess of alcohol. 
Masses of diseased wood finely divided, as well as masses 
of mycelium, were digested with cold water for 27 hours ; 
then to four parts of alcohol one part of the extract 
was added. A gray flocculent precipitate was obtained 
which on drying in a vacuum turned slightly darker. It 
was slightly soluble in water. Sections of Taxodium wood, 
young bean stems, etc., when placed in such a solution 
showed no perceptible change. As Hansen (1. c.) pointed 



* Marshall-Ward, H. On a lily disease. (Ann. Bot. 2 : 319. 1889.) 
t Fermi, Claudio. Weitere Untersuchungen iiber die typisclien En- 

zyme der Micro-organismen. (Cent, f . Bact. u, Parasitenkunde 10 : i04. 

1891.) 

X Hansen, A. Die Verfliissigung der Gelatine durch Schimmelpilze. 

(Flora n. s. 47:88. 1889.) 

§ Green, J. E. On Vegetable ferments. (Ann. Bot. 7 : 83. 1893.) 
II Smith, E. F. Sensitiveness of certain parasites to the acid juices 

of host plants. (Abstract in Bot. Gaz. 27 : 124. 1899.) 

41 



MISSOURI BOTANICAL GARDEN. 

out, this method of separating enzymes is very unsatisfac- 
tory, as it weakens the enzyme and may even destroy it. In 
this case it is probable that much of the precipitate consisted 
of soluble humus compounds, and as these are likewise 
precipitated by alcohol a separation becomes difficult. 

As the humus compound is insoluble in water (except a 
minute trace) it is difficult to add it to any culture media. 
It was dissolved in very weak KOH and added to agar and 
bouillon tubes which were inoculated with various bacteria 
and fungi. To a similar series of agar and bouillon tubes 
the KOH solution was added and likewise inoculated. In 
this double series no additional inhibitory effects due to the 
humus compound were evident. 

The conclusions arrived at in this chapter indicate that 
the humus compound found in the wood surrounding the 
holes is formed because of the action of a fungus on the 
ceU-walls of the wood, and that it is probably one of the 
products eifective in preventing the unlimited spread and 
destructive action of the disintegrating powers of that 
fungus. 

Age of the Fcngtjs. 

Taxodium distichum is an interesting tree in that it is one 
of the surviving members of a race of trees which were 
prominent in geologic times. Any disease which it is 
affected with may possibly have come down to the 
present day with its host. But few fungi are known in 
fossil condition, linger * describes mycelia from the wood 
of a Tertiary tree ; Williamson f figures a fungus, Pero- 
nosporites antiquarius from a stem of Lepidodendron (the 
same is also found in coal beds). Conwentz | found a 
mycelium in fossil wood of Rhizocupressinoxylon wiira- 



* Unger, F. Chloris protogaea. 1847. 

t Williamsoiij W. C. On the organization of fossil plants of the 
coal measures. — Calamites. (Phil. Trans. R. S. L. 161 : 477. 1871.) 

X Conwentz, H. Fossile Holzer von Karlsdorf am Zobten 27. 
Danzig. 1880. 
42 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

diatum. The mycelium had clamp connections and swell- 
ings like those of Agaricus melleus. 

In accounts given of Taxodium logs found buried at va- 
rious points * no mention is made of any defect. While in 
southern Louisiana last winter a number of sections of 
buried Taxodium logs were obtained. f These were found 
several miles back from the Mississippi river at an average 
depth of 10 ft. below Gulf level. Compared with other 
cypress logs found, these are not very old, but they are 
sufficiently far removed from the present time to deserve 
notice. In two of these logs unmistakable signs of pecki- 
ness were found. There was very little mycelium, but a 
sufficient number of hyphae with clamp connections were 
seen to justify the conclusion that they were the same as 
those growing to-day. The holes were few in number, but 
were not to be mistaken. It is probable that if other and 
older logs were examined more instances would be found. 
It would seem therefore that the disease is one which has 
extended back for some thousand years at least, and 
probably further. 



* Lyell, Sir Chas. Travels in N. A. in the years 1841-2. 1 : 114, — He 
says of cypress logs burled in the Dismal Swamp: "When thrown 
down they are covered by water, and never decompose except the sap." 

Lyell, Sir Chas. A second visit to the U. S. 249. (1850). — (Cypress 
buried at the mouth of the Altamaha river.) 

Carpenter, Wm. Account of the bituminization of wood in the 
human era, etc. (Am, Journ, of Sc, & Arts 36 : 118. 1839). — (Buried 
cypress forest at Port Hudson, La.) 

Bartram, W. Travels through North & South Carolina, Georgia, E. 
& W. Florida 66. London. 1792. 

f The logs were found at the following points : — 

No. 1. Standing stump 9 ft. below surface, 7850 ft. back from river on 
Jourdan ave. No. 2. Horizontal log, butt 30 inches; center 10 ft. below 
surface, 8325 ft. from river on Jourdan ave. Nos. 3 & 4. Standing stumps 
same locality as No, 1. No. 3 had 260 rings in the heart wood. The 
surface where the samples were taken reads about 21 Cairo datum, mean 
Gulf level, 21.26 C. D., i. e, they were therefore about 10 ft. below Gulf 
level. See also Chart No. 76 of the Mississippi River Commission, for 
location of Jourdan ave. 

43 



MISSOURI BOTANICAL GARDEN. 

If one considers the manner in wliich a fungus disease 
attacks plants at the present day, one will find that closely 
related plants are apt to be afflicted by the same disease. 
Thus Plasmopara Cubensis grows on a large number of 
genera of the Cucurbitaceae ; Gymnosporangium JSfidus Avis 
(Aecidiuin) on several genera of the Pomeae (^Posaceae) ; 
Trametes Pini on several genera of the Ooniferae, and so 
on. Judging by analogy, one might expect genera nearly 
related to Taxodium to be diseased similarly to Taxodium. 
There are but a few genera, closely related to Taxodium^ 
Avhich grow at the present time. In North America: 
Taxodium mucronatum is found in Mexico; Sequoia 
gigantea and 8. sempervirens, in California; Libocedrus 
decurrens, in CaUf ornia and Oregon; and the less closely 
related species of Juniperus. In addition to these there 
are a number of other species scattered over the globe, 
thus Libocedrus Douiana and L. Bidwillii in New 
Zealand, Libocedrus cupressoides and L. Chilensis in 
ChiU, also a dwarf species in Iceland. A closely related 
tree, Glyptostrobus Europaeus, is found in some of the 
southeastern provinces of China. All of these trees were 
common over the whole earth in Tertiary times, and if a 
disease was common to them then, one might expect to find 
that to-day. Of the species enumerated, the Sequoias are 
apparently free from diseases of the wood * while Libocedrus 
decurrens and the species of Juniperus so far seen, are affected 
by diseases which cause local rotting of the wood much like 
that of the cypress. Of the other trees nothing is known 
so far. The fungus which causes the decay in Libocedrus 
is described in the following, while that found in the trunks 
of Juniperus species is to be described in a separate paper 
soon to appear. 



Sargent, C. S. Silva of North America 10 : 140. 1896. 
44 



DISEASES OF TAXODIU3I AND LIBOCEDRUS. 
THE " PIN " DISEASE OF LIBOCEDRUS DECURRENS. 

Historical. 

In 1879 Harkness * published a note in which he called 
attention to a peculiar rot which occurs in the heart 
wood of the incense cedar, Lihocedrus decurrens. Mayr f 
mentions what is evidently the same disease and describes 
it as follows: " A certain fungus, Daedalea vorax^ appears 
to be very destructive, destroying the heart wood of stand- 
ing trees ; the fungus colors the wood red-brown and forms 
large lens-shaped cavities, at the same time the wood 
becomes very " briichig." In 1896 the following appeared 
in Sargent's Silva: t " The trunks of Lihocedrus decurrens 
are frequently honey-combed and its value destroyed as a 
timber tree by Daedalea vorax, which destroys rounded 
masses of wood, disposed in long rows, sometimes extend- 
ing through the length of the trunk, reducing them to a 
cinder-like powder." In the note published by Harkness 
one is led to believe that Daedalea vorax attacks Abies 
Douglasii, — not Lihocedrus. Daedalea vorax is reported 
as growing on Lihocedrus decurrens by Harkness. § In a 
letter received from Dr. Harkness last year he says; 
' ' Daedalea vorax is a fungus which causes the rot in Ahies 
Douglasii,'^ etc. As to the Lihocedrus disease he says : 
" Nothing could be found except mycelium which per- 
meates through the diseased portion. No visible signs of 
any spores were seen. A careful search fails to reveal 
any of the fungus either among the roots or the surface of 
the tree, nothing indeed to indicate its presence until the 
tree has been felled." He says furthermore that the note 



* Harkness, H. W. A foe to the lumberman. (Pacific Rural Press. 
Jan. 25, 1879.) 

t Mayr, Heinrich. Die Waldungen von Nordamerika 324. Mlinchen. 
1890. 

t Sargent, C. S. Silva of North America 10: 134. 1896. 

§ Harkness & Moore. Cat. of Pacific Coast fungi 12. (Read before the 
Cal. Acad, of Sciences, Feb. 2, 1880). 

45 



MISSOURI BOTANICAL GARDEN. 

ill the catalogue of Pacific Coast fungi which records 
Daedalea vorax on Lihocedrus (1. c.) is an error, and that 
instead of Lihocedrus it ought to read Abies Douglasii. 
Mayr's statement is therefore the only one ascribing this 
disease of Lihocedrus to Daedalea vorax, for the note in 
the Silva was based on the statements of Harkness 
and Mayr. In view of the fact that Mayr's report has 
never been confirmed I am inclined to the belief that 
Daedalea vorax has nothing to do with the decay of 
Lihocedrus. This would leave the identity of the fungus 
which is responsible for this trouble as obscure as in the 
case of Taxodium distichum. 

Character of the Disease. 

Specimens of diseased wood received from various parts 
of California and Oregon have the appearance shown in 
Plate 2. The heartwood is full of lens-shaped cavities 
filled with a very brittle brown material. The latter is evi- 
dently the wood which formerly filled the cavity, but has 
been changed and has shrunken considerably. The cavities 
are placed irregularly in the wood with their longest diam- 
eter parallel to the wood cells. They vary considerably in 
size, from 1 inch long and \ inch wide to 10 inches long 
and 1^ inches wide. In the majority of cases the separate 
cavities do not communicate with one another, but occa- 
sionally they do, as is e^ddent from the cavities at the right 
side of the fio-ure. The line of demarkation between sound 
wood and the brown decayed wood is a very sharp one. 
When the decayed wood is removed, the cavities have a 
sharply-defined, smooth bounding surface. In most 
respects the appearance of the wood is like that of diseased 

Taxodium wood. 

Occurrence. 

Concerning the prevalence and mode of occurrence of 
this disease, only such facts can be given as were learned 
from correspondents — particularly from Dr. Harkness, 
46 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

Mr. A. J. Johnson, and a number of lumber companies in 
California, Oregon, and Washington. The disease is one 
which resembles the one in the cypress in its method of 
growth. The decay begins somewhere in the upper part 
of a tree and proceeds both up and down, the lens-shaped 
cavities appearing at first as darker areas in the wood. 
Older trees are very liable to be diseased. One correspond- 
ent, from southern Washington, says: "The proportion 
of trees affected is very large. We might almost say that 
the trees are generally so aifected in this country." From 
Placer Co. , Cal. , another correspondent writes : " Probably 
more than one-half of the trees are affected in a e^reater 
or less degree." From intermediate points similar reports 
have been received. Young trees, i. e., such as are under 
12 inches in diameter, are not apt to be seriously diseased. 
Climatic and soil conditions seem to have as little influence 
on the prevalence of the disease, as they do in the case of 
pecky cypress. Wherever Libocedrus decurrens grows, 
the defect is also to be found, i. e., from central California 
northward, as far as it has been possible to learn. The 
diseased wood is quite durable and can be used for fence 
posts, scanthng, or for wood sills in buildings. The 
diseased wood is sold for $l-$3 less than sound cedar, 
per thousand ft. B. M., depending upon the degree 
of decay. This is an indication that it is at least 
capable of being used for some purposes. It might 
bo mentioned here that boards cut from trees of Juni- 
perus Virginiana affected with a similar disease were 
recently pulled off a barn where they had been 52 years. 
The Stimson Mill Co., of Ballard, Wash., writes: "We 
do not make any difference between sound and rotten 
cedar; $8 is the price for cedar delivered." 

Name, 

The only name which has been learned which is applied 
to this disease is "pin rot." The term "pecky" has 

47 



MISSOURI BOTANICAL GARDEN. 

been applied to a form of decay in the cypress in which the 
wood is destroyed in local pockets. As this is a distinct 
form of wood destruction I would apply the term ' ' pecky ' ' 
to all forms of destruction where pockets or holes are 
formed as in the cypress. One would therefore call the 
affected Libocedrus wood " pecky cedar." 

Structure of Diseased Wood. 

The normal wood of Libocedrus differs but little from that 
of Taxodium disticJium. Penhallow * places the two genera 
side by side. The diseased wood is decidedly different 
from the healthy wood. It has the appearance of a brown 
charcoal, breaks with a dull fracture and when pressed 
crumbles into a fine powder. In the mortar an impalpable 
dust is formed. In this respect it is very different from 
much-rotted cypress wood. In the latter the chemical 
transformation is far from uniform. Diseased Libocedrus 
wood is changed throughout ; both the spring and the sum- 
mer wood are changed, and very rapidly at that, i. e., 
there are no intervening steps as in Taxodium. A section 
made through the edge of a diseased pocket shows that at 
a certain point the cells are brown (PI. 4, fig. 2). It 
will be noted that the color of fig. 2 is the normal color of 
the wood. Hand in hand with this coloration goes a shrink- 
age of the middle lamella, so that the walls of the tracheids 
become much thinner. They have lost all tenacity. If a 
piece of charred wood is boiled in water for a few moments 
it can be pressed into any shape like a piece of dough. 
Sections on a slide can be pushed about so that the cells 
assume a rhomboidal shape, i. e., the whole acts like a net- 
work of fine flexible wire. This is to some extent visible in 
PI. 4, fig. 2, where a number of the walls are much bent, 
and do not have the rigid appearance of the healthy wood 



* Penhallow, D. P. Generic characters of N. A. Taxaceae & Coni- 
ferae. (Trans. Roy. Soc. Canada 11. 2 : 51. 1896.) 
48 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

(fig. 1). The shrinkage of the wall causes breaks to ap- 
pear in the pits (PL 5, fig, 11) and after a time in 
the walls (e). The shrinkage in a large mass of wood 
after a time becomes so great that the wood breaks at some 
point and gives rise to the appearance to be noted in 
the long hole at the left of the block in Plate 2. The 
three lamellae of the wood-cell are distinct even in greatly 
"charred" wood (PI. 4, fig. 2). 

The chemical nature of the wood cells has been entirely 
changed, and, as has been said, the change from sound 
wood to completely charred wood is immediate so far as 
microchemical tests can show. With dilute KOH the dis- 
eased wood swells to two or three times its size and the 
breaks in the walls close. A large per cent, is soluble 
in KOH and from such a solution humus compounds similar 
to those found in the cypress are obtained. Chlor-iodide 
of zinc turns the walls brown. When treated with dilute 
nitric acid the secondary lamellae gradually dissolve and 
there is left a skeleton framework composed of the primary 
lamella, the intercellular substance at the angle, and the 
fine membrane of the pits with the thickened torus. The 
solution takes place very gradually and can be followed very 
readily in a thin section. The nitric acid evidently dissolves 
out the substances into which the secondary lamella has 
been changed, leaving the more resistant primary lamella 
intact. From the HNO3 solution a heavy flocculent orange 
mass is precipitated when excess of water is added. This 
precipitate is very soluble in alcohol and acetic acid, 
slightly so in ammonia, insoluble in ether, chloroform, ben- 
zine or acids. When dissolved in absolute alcohol, and 
cooled, no crystals form, but an oily substance settles on 
the walls of the dish as the alcohol evaporates. No further 
attempt was made to determine what this is. Nitric acid 
and potassium chlorate dissolve the entire wood substance. 
With H2SO4 the walls turn black and swell considerably. 
Phloroglucin and hydrochloric acid stain the rotted wood 

49 



MISSOURI BOTANICAL GARDEN. 

carmine red verging toward orange, indicating the presence 
of coniferin. When treated for twelve hours with Javelle 
water and then stained with chlor-iodide of zinc the pri- 
mary lamella turns light brown ; with methylen blue it stains 
deep blue, indicating the presence of pectic substances.* 
The skeleton framework obtained after treatment with 
nitric acid stains blue with cellulose stains. This behavior 
towards various reagents shows that most of the cellulose 
has been removed and that the lignin substances have been 
transformed into substances readily soluble in nitric acid. 
A number of chemical analyses were made of charred 
wood, following the method given by Allen f for determin- 
ing the compounds found in wood. The wood was finely 
rasped and pulverized and dried at 100° C. After an 
aqueous extraction, the wood was extracted with alcohol 
and then with ether. 8.33% was found soluble in alcohol. 
The dried residue was hard, and broke with a bright frac- 
ture. It had all the attributes of a resin. Small quanti- 
ties of pectic substances were found present, and a number 
of other products which were not determined. The rotted 
wood does not restore polarized light. 

Wood Between the Holes. 
The wood between the rotted areas is, as in Taxodium^ 
perfectly sound as far as its structure is concerned. It 
reacts with reagents similarly to healthy wood. In the 
ceUs immediately surrounding the diseased spots, especially 
in the wood parenchyma and meduUary rays, a red-brown 
substance is always present, which fiUs the cells as with 
plugs. It is very resistant toward acids and while boiling 
nitric acid dissolves the wood it does not affect this sub- 
stance. Oxalic acid turns it black very quickly, also 
potassium bichromate and iron salts. These reactions 



* Mangin, A. Sur la presence des composes pectiques dans les v6g6- 
taux, (Comptes rend. etc. 109:577. 1889.) 

t Allen, A. A. Commercial organic analysis 1 :323. 1898. 

60 



DISEASES OP TAXODIUM AND LIBOCEDRUS. 

would place it with the tannins. Hartig found tannin 
in decayed wood, whereas it was not present in sound 
wood, and in the present case there seems to be a similar 
instance. "What the origin of the tannin may be I do not 
venture to say. 

Aside from the tannin a brown humus compound, similar 
to that found in Taxodium, occurs. It is found in the 
form of irregular granular masses which readily dis- 
solve in dilute KOH. The medullary rays in particular 
are filled with this substance (PI. 4, fig. 2) ; it seems 
to permeate the cell-walls, for these turn the characteristic 
yellowish-brown color on addition of KOH, and the tra- 
cheids become filled with the brown liquid. Extractions of 
the surrounding wood with KOH yield considerable quan- 
tities of the compound. Nowhere were any dried plates 
found, such as were described for the cypress. 

Mycelium and Spores. 

The mycelium found in the diseased Libocedrus wood 
agrees so closely in appearance with that found in the 
Taxodium that the drawing on PI. 5, fig. 1 may represent 
it as well. Few hyphae are to be found in the charred 
wood or the wood about the holes. Abundant evidence of 
their having been present is seen in the numerous holes 
which puncture the walls of the charred wood in all direc- 
tions (PI. 4, fig. 2). No preference is shown for the 
pits. The hyphae are most abundant in wood away from 
the rotted holes. They are colorless, branch frequently 
and are provided with a large number of clamp connec- 
tions. The finest threads pass through the walls in all 
directions. Between the rotted areas the hyphae usually 
extend directly from hole to hole, just as in the Taxodium. 
In places the mycelium collects in large masses or felts ; in 
these felts the hyphae are matted. Many crystals of 
calcium oxalate give the whole a white appearance. 

A brown mycelium like that found in the cypress was 

51 



MISSOURI BOTANICAL GARDEN. 

found fn a number of cases. How common this is cannot 
be said, as the number of specimens examined was from 
but a small number of trees. The threads have marked 
attachment organs (PL 5, fig. 9 "d-f ") which have 
been described under the cypress disease. 

In the rotted wood, and particularly around the same, the 
cells are often filled with great masses of spores like those 
seen in isolated cases in the cj^press (PI. 5, fig. 2). These 
spores are present in such numbers, that they often com- 
pletely fill the tracheids. Several spores were found with 
very fine hyphae attached (fig. 5) and many showed small 
knobs at one end. It will be necessary to see a large num- 
ber of trees to determine where these spores came from. 

Localization. 

The localization of the diseased areas is quite as marked 
in Libocedrus as it is in Taxodium. One may have a 
block of wood 3X3X1 in. which looks perfectly sound, but 
when split longitudinally it may contain a sharply defined 
lenticular hole. It is suggested that probably similar 
reasons to those given for the cypress hold here. The 
investigation with respect to this point is to be regarded as 
but begun. When it becomes possible to grow the fungus 
found in the holes one may expect to reach more decisive 
conclusions. 

SUMMARY. 

In the foregoing, two forms of decay have been de- 
scribed, one destroying wood of Taxodium distichum^ the 
other of Libocedrus decurrens. In both cases the wood 
is destroyed in localized areas, which are surrounded by 
apparently sound wood. The cell-walls are changed into 
compounds which diffuse through the walls and fill the cells 
surrounding the decayed center ; and these have been called 
humus compounds. In both, a fungus mycelium occurs 
with strongly marked characteristics, which flourishes 
52 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

within the diseased centers and grows between these 
centers without a:ffecting the intervening wood. This wood 
can be utilized for many purposes even when much rotted, 
and in neither case does the mycelium grow after the tree 
has once been cut down. The two trees thus diseased, 
both representatives of a race of trees the majority of 
which are extinct, are closely related genetically, although 
growing in different parts of the country. The two forms 
of decay differ but slightly, and not more than might be 
expected in two woods of different character. Taking those 
facts into consideration, it appears probable that the two 
diseases are caused by one and the same fungus, the fruiting 
form of which has not yet been found. 



EXPLANATION OF PLATES ILLUSTRATING DISEASES OF 
TAXODIUM AND LIBOCEDRUS. 

Plates 1, 2, plate 4, fig. 3, and the coloring of plate 3, 
fig. 2, and plate 4, fig. 2, were prepared under my direction 
by Miss Harriet P. Learned. 

Plate 1. — 1, Branch of Taxodium distichum, showing early stage of 
the pecky disease. The wood turns yellow in longitudinal lines (XD* 
2, A block of Taxodium distichum cut from the heart of a tree several 
hundred years old, showing advanced stage of peckiness. In a large 
number of trees the rotted portion is more yellow than that shown in the 
figure (XI). 

Plate 2. — A block of Libocedrus dectirrens showing advanced stage of 
the pecky disease. The rotted wood has fallen out from the holes at the 
tight of the figure leaving a smooth surface (Xi)' 

Plate 3. — 1, Transection of pecky cypress wood. The section was 
made so as to include some of the much rotted wood, seen at the bottom 
of the figure, also some of the sound wood. It was stained with phloro- 
glucin and HCl. The violet of the original section was somewhat more 
marked than is the color in the figure. The portions staining violet indi- 
cate wood which has not been affected by the fungus, those staining 
yellow show where the conif erin elements have been extracted : « m ' 
medullary rays ; • k ' cell- walls from which the conif erin has been ex- 
tracted ; ' p ' normal cell-wall ; « d ' primary lamella resisting the disinte- 
grating factor longer than the secondary lamellae ; ' h ' perforation of 
cell-wall made by fungus hypha (magnification same as flg. 2) . 2, Tran- 

53 



MISSOURI BOTANICAL GARDEN. 

section of pecky cypress wood, showing the transition from sound wood 
to humus compound, after staining with phloroglucin and HCl. : * g ' 
primary lamella, unaffected ; ' p ' small masses of humus compound 
resulting apparently from the transformation of the tertiary lamella; ' i ' 
wood staining yellow, an intermediate stage between the sound wood and 
the humus compound ; ' h ' a thicker layer of humus compound than 
the one indicated at ' p ' ; ' c ' a still more advanced stage in the humus 
formation; *e' the entire cell-wall has been transformed into the 
humus compound; 'u' piece of cell -wall not yet changed to humus 
compound. 

Plate 4. — 1, Transection of sound wood of Libocedrus decurrens, 
showing spring and summer wood : ' h ' brown hypha with attachment 
organs ; * s ' spores often found in the wood cells. 2, Transection of 
diseased wood of Libocedrus decurrens, i. e. wood from one of the pockets. 
The color is the natural color of the wood. The medullary ray is filled 
with brown humus solution. 3, Block of Taxodium distichum showing 
pecky hole lined with white fibers, consisting of pure cellulose (XJ)- ^t 
Two tracheids from wood surrounding a diseased spot in Taxodium 
distichum. The tracheids are filled with brown humus compound which 
has cracked in drying. 

Plate 5. — 1, Mycelium from decayed wood of Taxodium distichum, 
showing the numerous clamp connections. 2, Spores from pecky wood 
of Libocedrus decurrens. (The line at the top is IOa*') 3, Portion of a 
tracheid near diseased area of Taxodium distichum. The pits appear 
corroded because of a peculiar arrangement of resin globules. (Magni- 
fication same as fig. 2.) 4, Brown chlamydospores from rotted wood 
of Taxodium distichum. 5, Brown spores from wood of Taxodium dis- 
tichum. These are like the ones found in the red cedar. 6, Spores from 
wood of Quercus alba destroyed by Polyporus sulphureus (from Will- 
iamsville, Mo. ; magnification same as fig 5). 7, Spores from wood of 
Taxodium distichum, resembling Willkomm's Xenodochus ligniperda. 8, 
Minute bodies, which appear in the humus compound when the latter is 
slowly dissolved away. Two views are represented (magnification same 
as fig. 2). 9, Mycelium showing attachment organs: * a-c ' from wood 
of Taxodium distichum; ' d-f ' from wood of Libocedrus decurrens, 10, 
Longisection of pecky cypress wood, showing gradual disintegration of 
the tracheids : ' a ' normal tracheid filled with humus compound ; ' b ' 
similar tracheid with colorless mycelium ; ' c ' tracheid with pits looking 
as if corroded ; ' d ' tracheids with walls which are beginning to contract ; 
' e ' tracheid in which the walls show spiral cracks ; ' f ' and ' g ' tracheids 
showing final stages in the process of solution. (Magnification same 
as fig. 1.) 11, Longitudinal section through pecky wood of Libocedrus 
decurrens: 'a' normal tracheid; 'b' tracheid showing beginning of 
disintegration, the pits show cracks, some spores are collected near 
a wall ; ' c ' and ' d ' tracheids which have contracted considerably, show- 
ing cracks in the pits and the wall. (Magnification the same as the pre- 
ceding figure.) 
54 



DISEASES OF TAXODIUM AND LIBOCEDRUS. 

Plate 6. — Upper figure a pile of pecky cypress boards at Lutcher, La. 
The boards have been exposed some time, so that the rotted wood has 
been washed from the holes. The lower figure is a photograph of the 
vertical banks of a ditch on Dauphin St., Mobile, Ala. (in front of the 
house of Dr. Chas. Mohr) . The bank is lined with pecky cypress boards, 
which are held in place by horizontal braces. 

55 



Reft. Mo. Bot. Gard., Vol. 11. 



Plate 1. 




PEOKY CYPRESS. 



Reft. Mo. Box. Gard., Vol. li 




PECKl INCENSE CEDAR. 



Rept. Mo. Box. Gard., Vol. 11. 



Plate 3 




PEOKY CYPRESS. 



Kkpt Mo. Box. (takd., Vol. 11. 



Plate 4. 




PECKY CYPRESS AND CEUAR. 



Rept. Mo. Bot. Card., Vol. ii. 



Plate 5 




PECKY CYPRESS AND CEDAR. 



Rept, Mo. Rot. Garh., Vol. 11. 



Pl^te 6. 




PECKY CYPRESS. 



% 



LIBRARY OF CONGRESS 




002 811 939 2 



'''ffr^^ 










